A 100 Mpc$^2$ structure traced by hyperluminous galaxies around a massive $z$ = 2.85 protocluster

George C. P. Wang; Scott C. Chapman; Nikolaus Sulzenauer; Frank Bertoldi; Christopher C. Hayward; Ryley Hill; Satoshi Kikuta; Yuichi Matsuda; Douglas Rennehan; Douglas Scott; Ian Smail; Charles C. Steidel

arXiv · 2406.16637

A 100 Mpc$^2$ structure traced by hyperluminous galaxies around a massive $z$ = 2.85 protocluster

George C. P. Wang·Scott C. Chapman·Nikolaus Sulzenauer·Frank Bertoldi·Christopher C. Hayward·Ryley Hill·Satoshi Kikuta·Yuichi Matsuda·Douglas Rennehan·Douglas Scott·Ian Smail·Charles C. Steidel

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Abstract

We present wide-field mapping at 850 $\mu$m and 450 $\mu$m of the $z$ = 2.85 protocluster in the HS1549$+$19 field using the Submillimetre Common User Bolometer Array 2 (SCUBA-2). Spectroscopic follow-up of 18 bright sources selected at 850 $\mu$m, using the Nothern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter Array (ALMA), confirms the majority lies near $z$ $\sim$ 2.85 and are likely members of the structure. Interpreting the spectroscopic redshifts as distance measurements, we find that the SMGs span 90 Mpc$^2$ in the plane of the sky and demarcate a 4100 Mpc$^3$ "pancake"-shaped structure in three dimensions. We find that the high star-formation rates (SFRs) of these SMGs result in a total SFR of 20,000 M$_\odot$ yr$^{-1}$ only from the brightest galaxies in the protocluster. These rapidly star-forming SMGs can be interpreted as massive galaxies growing rapidly at large cluster-centric distances before collapsing into a virialized structure. We find that the SMGs trace the Lyman-$\alpha$ surface density profile. Comparison with simulations suggests that HS1549$+$19 could be building a structure comparable to the most massive clusters in the present-day Universe.

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George C. P. Wang, Scott C. Chapman, Nikolaus Sulzenauer, Frank Bertoldi, Christopher C. Hayward, Ryley Hill, Satoshi Kikuta, Yuichi Matsuda, Douglas Rennehan, Douglas Scott, Ian Smail, Charles C. Steidel. 2024-06-24. A 100 Mpc$^2$ structure traced by hyperluminous galaxies around a massive $z$ = 2.85 protocluster. https://arxiv.org/abs/2406.16637

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